This invention relates to self-propelled apparatus and more particularly to a unique drive actuator for a self-propelled sweeper and the like.
Various forms of self-propelled apparatus such as lawn mowers, vacuum cleaners, carpet and industrial sweepers and the like are presently available. Such devices typically include an internal combustion engine or an electric motor for driving at least one ground engaging wheel as well as the operative elements of the device such as a mower blade, a sweeper brush, a blower and the like.
In order to properly control these devices, proposals have been made for selectively transmitting power from the engine or motor to the ground engaging wheel by movement of an operator's control handle. It is preferred that power be transmitted to the ground engaging wheel only when the control handle is shifted by the operator so that upon release of the control handle the machine will stop. An example of one such prior proposal may be found in U.S. Pat. No. 3,323,295 to Cavanaugh, entitled POWER LAWN MOWERS, and issued on June 6, 1967. This patent discloses a drive actuator which upon pivotal movement of a control handle, shifts a driven friction wheel mounted on a bell crank into contact with a ground engaging wheel. The driven friction wheel is rotated by a pulley and endless belt arrangement from the drive motor for the lawn mower. Another example of the prior art approaches may be found in U.S. Pat. No. 3,040,504 to Wilkin, entitled POWER LAWN MOWER AND STEERING MEANS THEREFOR, and issued on June 26, 1962. This patent is an example of the prior art constructions wherein movement of a control handle shifts an idler wheel or pulley to tension a drive belt so that power is transmitted from an engine or motor to the ground engaging wheels.
The prior art devices have suffered from various problems primarily related to complexity, reliability, durability and operational difficulties.